Press brake tool holder incorporating tool-seating mechanism

ABSTRACT

Press brake tool holders suitable for holding press brake tools for punching and/or otherwise deforming workpieces, such as sheet metal. Provided in some embodiments is a press brake tool holder. Some embodiments provide the tool holder in combination with a press brake tool. Methods of using press brake tool holders are also provided. In certain embodiments, the tool holder has a tool-seating mechanism adapted for moving a tool parallel to a pressing axis of the tool holder.

RELATED APPLICATIONS

This is a continuation application of, and claims priority toInternational Application No. PCT/US2006/027064 filed Jul. 11, 2006, theteachings of which are incorporated herein by reference, and also claimspriority to U.S. patent application Ser. No. 11/178,977 filed Jul. 11,2005.

FIELD OF INVENTION

The present invention relates generally to industrial presses. Moreparticularly, this invention relates to press brakes.

BACKGROUND OF INVENTION

Press brakes are commonly used to bend or otherwise deform sheet-likeworkpieces, such as sheet metal workpieces. A conventional press brakehas an upper beam and a lower beam, at least one of which is movabletoward and away from the other. Typically, the upper beam is movablevertically while the lower beam is fixed in a stationary position. It iscommon for a male forming punch and a female forming die to be mountedrespectively on the upper and lower beams of a press brake.

Typically, the punch has a downwardly oriented, workpiece-deformingsurface (or “tip”). The configuration of this surface is dictated by theshape into which it is desired to deform a workpiece. The die typicallyhas a recess (bounded by one or more workpiece-deforming surfaces) thatis aligned with the tip of the punch. The configuration of this recesscorresponds to the configuration of the punch's tip. Thus, when thebeams are brought together, a workpiece between them is pressed by thepunch into the die to give the workpiece a desired deformation (e.g., adesired bend).

In order to accurately deform a workpiece, it is necessary for the toolsto be mounted securely on the tool holder. This is accomplished byforcibly clamping the tool holder about each tool. Multiple steps aresometimes required, for example, to mount a punch on the upper beam of apress brake. The punch may be moved into an initial-mount position bylifting the shank of the punch upwardly between a support plate andclamp of the tool holder. In some cases, when the punch is moved intothis position, a safety key of the punch engages a safety slot of thetool holder. In other cases, a safety groove on the punch is engaged bya lip on the clamp of the tool holder. Either way, the tool holdersubsequently is clamped forcibly on the shank of the punch. Even at thisstage, the load-bearing surfaces of the tool holder and punch may not besecurely engaged. Rather, additional steps may be required. For example,with many tool holder designs, the upper and lower tables of the pressbrake must subsequently be moved together until the punch comes intocontact with a die on the lower table. By forcing the tip of the punchagainst the die, the punch can be urged upwardly relative to the toolholder until the load-bearing surface(s) of the punch is/are moved intocontact with the corresponding load-bearing surface(s) of the toolholder. When a punch is in this operative position, the load-bearingsurfaces of the tool holder and punch are engaged and the shank of thepunch is forcibly clamped, e.g., between a support plate and clamp ofthe tool holder. During pressing operations, the punch is maintained inthis position. Thus, it can be appreciated that several steps may berequired to operatively mount a punch on the upper beam of a pressbrake.

It would be desirable to provide a tool holder that can be operativelyclamped about a tool in such a way that the load-bearing surfaces of thetool holder and tool are engaged as an adjunct of the closing action ofthe tool holder on the tool (e.g., without having to press the tip of apreliminarily-clamped punch against a die on the lower table of thepress brake). It would be particularly desirable to provide a toolholder that offers tool-seating functionality and can be used with awide variety of tooling styles. The present invention provides new pressbrake tool holder technologies, in which a tool-seating mechanism isincorporated into the tool holder.

SUMMARY OF INVENTION

Some press brake tool holders are limited in terms of the tooling stylesthey are able to accommodate. This is the case, for example, withcertain tool holders that offer tool-seating functionality. The presentinvention, in some embodiments, provides a tool holder having atool-seating mechanism that can be used with a wide variety of differenttooling styles. In such embodiments, this is advantageous in that theoperator of such a tool holder is able to use tools of many differentstyles without having to provide an adaptor or the like for the toolholder.

In certain embodiments, the invention provides a tool holder for a pressbrake. The tool holder is adapted to move a press brake tool along apressing axis when the tool is operatively mounted on the tool holder.The tool holder has two spaced-apart confronting walls bounding atool-mount channel configured for receiving a shank of the tool. In thepresent embodiments, the walls have clamping surfaces for engaging andclamping the tool's shank there between.

Preferably, the tool holder includes confronting movable seating membersdisposed on opposite sides of the tool-mount channel, the seatingmembers being adapted to engage opposite sides of the tool's shank andto move together with the shank in a direction at least generallyparallel to the tool holder's pressing axis in response to a first ofthe two walls moving toward a second of the two walls.

In certain embodiments, the invention provides a method of mounting apress brake tool on a tool holder having a tool-mount channel bounded bytwo spaced-apart confronting walls. The walls have clamping surfaces forengaging and clamping a shank of the tool there between as a first ofthe walls is moved toward a second of the walls. The tool holder isadapted for moving the tool when operatively mounted on the tool holderalong a pressing axis. In the present embodiments, the tool holder hasconfronting movable seating members disposed on opposite sides of thetool-mount channel. The method comprises positioning the tool's shank inthe tool-mount channel, moving the first wall toward the second wallsuch that the seating members engage opposite sides of the tool's shank,and moving the thus engaged seating members together with the tool'sshank in a direction at least generally parallel to the tool holder'spressing axis.

In certain embodiments, the invention provides a tool holder for a pressbrake. The tool holder is adapted to move a press brake tool along apressing axis when the tool is operatively mounted on the tool holder.The tool holder has two spaced-apart confronting walls bounding atool-mount channel configured for receiving a shank of the tool. In thepresent embodiments, the tool holder has first and second moveableseating members disposed on opposite sides of the tool-mount channel. Inthe present embodiments, the first and second seating members areadapted to respectively engage first and second sides of the tool'sshank and to move together with the shank in a direction at leastgenerally parallel to the tool holder's pressing axis in response to afirst of the two walls moving toward a second of the two walls.

In certain embodiments, the invention provides a tool holder for a pressbrake. The tool holder is adapted to move a press brake tool in apressing direction when the tool is operatively mounted on the toolholder. The tool holder has two spaced-apart confronting walls boundinga tool-mount channel. In the present embodiments, the tool holder has amoveable seating member mounted on one of the confronting walls. Thisseating member has a contact surface that comes into direct contact witha side of the tool's shank when the shank is received in the tool-mountchannel and a first of the two walls is moved toward a second of the twowalls. The contact surface once moved into direct contact with the sideof the tool's shank delivers a frictional force to the tool's shank. Thefrictional force is oriented in a seating direction (e.g., in a verticaldirection) at least generally opposed to the tool holder's pressingdirection. Preferably, this frictional force is the only seating force(e.g., the only upward component of force) applied by the seating memberto the tool when the tool's shank is received in the tool-mount channeland the first wall is moved toward the second wall.

In certain embodiments, the invention provides a tool holder for a pressbrake. The tool holder is adapted to move a press brake tool along apressing axis when the tool is operatively mounted on the tool holder.The tool holder has two spaced-apart confronting walls bounding atool-mount channel. In the present embodiments, the tool holder includesa clamp that is moveable between open and closed positions. Preferably,the tool holder includes a moveable seating member mounted on one of theconfronting walls. In the present embodiments, when a shank of the toolis received in the tool-mount channel and the clamp is moved from itsopen position to its closed position the seating member engages thetool's shank and moves together with the shank in a direction at leastgenerally parallel to the tool holder's pressing axis until aload-receipt surface of the tool engages a load-delivery surface of thetool holder. In the present embodiments, the tool holder can optionallyinclude a spring member resiliently biasing the clamp toward its closedportion.

In certain embodiments, the invention provides a tool holder for a pressbrake. The tool holder is adapted to move a press brake tool in apressing direction when the tool is operatively mounted on the toolholder. The tool holder has two spaced-apart confronting walls boundinga tool-mount channel. In the present embodiments, the tool holder has amoveable seating member mounted on one of the confronting walls, and theseating member has a contact surface that comes into direct contact witha side of the tool's shank during a closing of the tool holder on thetool's shank. In the present embodiments, the contact surface is definedat least in part (optionally substantially entirely by) by a polymer.

In certain embodiments, the invention provides a tool holder for a pressbrake. The tool holder is adapted to move a press brake tool along apressing axis when the tool is operatively mounted on the tool holder.The tool holder has two spaced-apart confronting walls bounding atool-mount channel configured for receiving a shank of the tool. In thepresent embodiments, the tool holder includes moveable seating membersdisposed on opposite sides of the tool-mount channel. In theseembodiments, the seating members preferably are adapted to engageopposite sides of the tool's shank and to move together with the shankin a direction at least generally parallel to the tool holder's pressingaxis in response to a first of the two walls moving toward a second ofthe two walls. In the present embodiments, the seating members areadapted to bear against, and cam with, respective cam surfaces of thetool holder during this conjoint movement of the seating members and thetool's shank. Further, in the present embodiments, the cam surfaces ofthe tool holder are defined by bodies (optionally a tool holder blockand a moveable face plate) comprising or consisting essentially of afirst material, the seating members comprise a second material, and thefirst and second materials are different. Optionally, the first materialcomprises a steel and the seating members are formed of material havinga lesser hardness than the steel. The second material can optionallycomprise a polymer. In some cases, the seating members consistessentially of polymer and filler.

In certain embodiments, the invention provides a tool holder for a pressbrake. The tool holder is adapted to move a press brake tool along apressing axis when the tool is operatively mounted on the tool holder.The tool holder has two spaced-apart confronting walls bounding atool-mount channel configured for receiving a shank of the tool. In thepresent embodiments, the walls have clamping surfaces for engaging andclamping the tool's shank therebetween. In the present embodiments, theclamping surfaces of the tool holder preferably are defined by metal(optionally steel) over which coating is provided. The coating canoptionally comprise nitrogen and/or carbon. In the present embodiments,the seating members can optionally comprise a polymer. In some cases,they consist essentially of the polymer and a filler.

In certain embodiments, the invention provides a tool holder for a pressbrake. The tool holder is adapted to move a press brake tool in apressing direction when the tool is operatively mounted on the toolholder. The tool holder has two spaced-apart confronting walls boundinga tool-mount channel. The tool holder has a moveable seating membermounted on one of the confronting walls. In the present embodiments, theseating member has a contact surface adapted to directly contact a sideof the tool's shank. In the present embodiments, the seating member hasa camming surface adapted to bear against, and cam with, a cam surfaceof the tool holder. Preferably, in the present embodiments, the camsurface of the tool holder is defined by metal (optionally a steel) overwhich coating is provided. The coating can optionally comprise nitrogenand/or carbon. The camming surface of the seating member can optionallybe defined at least in part by a polymer. For example, the seatingmember can optionally consist essentially of the polymer and a filler.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a tool holder in accordance with certainembodiments of the invention;

FIG. 2 is an exploded perspective view of a tool holder in accordancewith certain embodiments of the invention;

FIG. 3 is a front end view of a tool holder in accordance with certainembodiments of the invention;

FIG. 4 is a cross-sectional side view of the tool holder of FIG. 3, thecross section being taken along lines F-F;

FIG. 5 is a cross-sectional side view of the tool holder of FIG. 3, thecross section being taken along lines E-E;

FIG. 6 is a partially broken-away side view of a tool holder inaccordance with certain embodiments of the invention;

FIG. 7 is a partially broken-away cross-sectional side view of a toolholder in accordance with certain embodiments of the invention;

FIG. 8 is a side view of a tool holder block that is part of a toolholder in accordance with certain embodiments of the invention;

FIG. 9 is a perspective view of a moveable plate that is part of a toolholder in accordance with certain embodiments of the invention;

FIG. 10 is a perspective view of a moveable plate that is part of a toolholder in accordance with certain embodiments of the invention;

FIG. 11 is a perspective view of a seating member that is part of a toolholder in accordance with certain embodiments of the invention;

FIG. 12 is a side view of a seating member that is part of a tool holderin accordance with certain embodiments of the invention;

FIG. 13 is a perspective view of a clip member that is part of a toolholder in accordance with certain embodiments of the invention;

FIG. 14 is a side view of a tool on a tool holder in accordance withcertain embodiments of the invention;

FIG. 15 is a partially broken-away side view of a tool on a tool holder,the tool being shown in its operatively-clamped position, in accordancewith certain embodiments of the invention;

FIG. 16 is a partially broken-away side view of a tool holder inaccordance with certain embodiments of the invention;

FIG. 17 is a partially broken-away cross-sectional side view of a toolholder in accordance with certain embodiments of the invention;

FIG. 18 is a partially broken-away side view of a tool holder inaccordance with certain embodiments of the invention;

FIG. 19 is a partially broken-away side view of a tool holder inaccordance with certain embodiments of the invention;

FIG. 20 is a partially broken-away side view of a tool holder inaccordance with certain embodiments of the invention;

FIG. 21 is a partially broken-away side view of a tool holder inaccordance with certain embodiments of the invention;

FIG. 22 is a partially broken-away cross-sectional side view of a toolholder in accordance with certain embodiments of the invention;

FIG. 23 is a partially broken-away cross-sectional perspective view ofthe tool holder of FIG. 22;

FIG. 24A is a partially broken-away side view of a tool holder inaccordance with certain embodiments of the invention;

FIG. 24B is a perspective view of an exemplary wedge member that can beused for a tool holder in accordance with certain embodiments of theinvention;

FIG. 25 is a partially broken-away perspective view of a tool holder inaccordance with certain embodiments of the invention;

FIG. 26 is a schematic cross-sectional side view of a tool holder inaccordance with certain embodiments of the invention;

FIG. 27 is a schematic cross-sectional side view of a tool holder inaccordance with certain embodiments of the invention;

FIG. 28 is a schematic cross-sectional side view of a tool holder inaccordance with certain embodiments of the invention;

FIG. 29 is a schematic side view of a coated tool holder block inaccordance with certain embodiments of the invention;

FIG. 30 is a front view of a tool holder in accordance with certainembodiments of the invention;

FIG. 30A is one side end view of the tool holder of FIG. 30;

FIG. 30B is another side end view of the tool holder of FIG. 30;

FIG. 31 is a cross-sectional view of the tool holder of FIG. 30 takenalong lines A-A;

FIG. 32 is a cross-sectional view of the tool holder of FIG. 30 takenalong lines B-B;

FIG. 33 is a cross-sectional view of the tool holder of FIG. 30 takenalong lines C-C;

FIG. 34 is a cross-sectional view of the tool holder of FIG. 30 takenalong lines D-D;

FIG. 35 is a perspective view of the tool holder of FIG. 30 as seen fromone perspective; and

FIG. 36 is a perspective view of the tool holder of FIG. 30 as seen fromanother perspective.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention in some embodiments provides a brake press tool holder TH.Generally, the tool holder TH defines a channel C configured forreceiving the shank of a press brake tool. This channel C is referred toherein as the tool-mount channel. In some embodiments, the tool-mountchannel C has a generally T-shaped cross section, although this is by nomeans required. Preferably, at least part of the channel C is bounded bytwo confronting walls CW, CW′ of the tool holder. Optionally, theconfronting walls CW, CW′ are at least generally vertical and/or eachdefine at least one surface that is at least substantially vertical andplanar. These features, however, are not required. For example, theconfiguration and construction of the walls CW, CW′ bounding thetool-mount channel C will vary depending upon the particular style inwhich the tool holder is embodied.

The tool holder TH will commonly be adapted for use with American styletools. However, the tool holder can take the form of various other toolholder styles known in the art, including those currently in lesswidespread use. Moreover, the tool holder TH can be adapted for use withtooling styles that are not yet developed but would benefit from thefeatures of this invention. The tool holder, of course, can be a pressbrake beam, an adaptor mounted to a press brake beam, or any other typeof press brake tool holder.

Some embodiments of the invention provide a tool holder TH incombination with a press brake tool TL. The press brake tool TL can be amale forming punch or a female forming die. Typically, the tool TL hasgenerally opposed first and second ends (or sides). The first end (orside) of the tool preferably defines a workpiece-deforming surface(e.g., at a tip of the tool) configured for making a desired deformation(e.g., a bend) in a workpiece when this surface is forced against theworkpiece (e.g., when a tip of the tool is forced against a piece ofsheet metal or the like). The second end (or side) of the tool has ashank (or “tang”) S configured for being mounted in (e.g., sized andshaped to be received in) the tool-mount channel C.

In some cases, the tool TL has a safety key SK. As shown in FIGS. 14 and15, the shank S of the tool TL can optionally have a safety key SKadapted for engaging a safety recess (or “safety groove”) SR, and/ormoving into alignment with a safety shelf SCS, defined by the toolholder TH. When provided, the safety key SK can be retractable ornon-retractable. Safety keys of both types are described in U.S. Pat.No. 6,467,327 (Runk et al.), and U.S. patent application Ser. No.10/742,439, entitled “Press Brake Tooling Technology”, the entirecontents of each of which are incorporated herein by reference.

In embodiments involving a tool TL with a safety key SK, the keypreferably comprises an engagement portion 580 that is adapted toproject into a safety recess SR (and/or into alignment with a safetyshelf SCS) defined by the tool holder TH. In the case of anon-retractable safety key, the key will typically comprise a rigidprojection from the tool's shank. When provided, the non-retractablesafety key preferably is either integral to the tool's shank or rigidlyjoined to the tool's shank.

In the case of a retractable safety key, the key is mounted on the toolso as to be moveable between an extended position and a retractedposition. In more detail, such a key preferably comprises a rigidengagement portion 580 that is moveable (e.g., laterally) relative to(e.g., generally toward and away from) the tool's shank (or at leastrelative to stationary portions of the shank). Such retractable safetykeys are described in U.S. Pat. No. 6,467,327 and U.S. patentapplication Ser. No. 10/742,439. In some cases, the safety key is partof a key assembly (e.g., mounted inside and/or on the tool) comprisingat least one spring member resiliently biasing (directly or via one ormore link members and/or other bodies) the safety key SK toward itsextended position.

Thus, in some embodiments, the tool holder defines a safety recess SR.When provided, the safety recess SR is sized to receive an engagementportion 580 of a desired safety key SK. In some embodiments involving atool TL with its shank S received in the channel C of a tool holder TH,the tool holder has a safety recess SR that is at the same elevation asa safety key SK (or at least an engagement portion thereof) on the tool.Some embodiments of this nature provide a tool TL having a safety key SKprojecting generally away from the shank S of the tool and engaged with(e.g., extending into) the safety recess SR of the tool holder TH, suchthat an engagement portion 580 of the safety key is received in thesafety recess (and is positioned directly above a safety shelf SCS ofthe tool holder). Reference is made to FIGS. 14 and 15.

Thus, certain embodiments provide a tool holder TH and tool TL incombination. In these embodiments, the second end of the tool (e.g., theshank S) is received in the tool holder's channel C. As noted above, thechannel C is typically bounded (at least in part) by two confrontingwalls CW, CW′ of the tool holder. In combination embodiments, the tool'sfirst end (which typically defines a tip) projects (e.g., generallyvertically) away from the tool holder.

Generally, the tool holder TH has at least one load-delivery surface LDconfigured for engaging a load-receipt surface LR of a press brake toolTL. Preferably, the tool holder TH has one or more generally orsubstantially horizontal load-delivery surfaces LD each being adapted toengage and deliver force to (when the tool is operatively mounted on thetool holder) one or more corresponding generally or substantiallyhorizontal load-receipt surfaces LR of the tool TL. In some embodimentsinvolving a tool in combination with (and operatively mounted on) a toolholder, the tool holder has a load-delivery surface LD engaged with(e.g., carried directly against) a load-receipt surface LR of the toolTL. Preferably, these engaged surfaces LD, LR are generally orsubstantially horizontal. In some cases, the tool holder TH has twohorizontal load-delivery surfaces LD. For example, FIGS. 1, 2, 4-7, and14-21 depict tool holders of this nature, wherein two load-deliverysurfaces LD are separated by an opening of the tool-mount channel C.Here, the channel C is depicted as being downwardly open. The invention,however, also provides embodiments where the channel C is upwardly open(e.g., embodiments where the tool holder is used to secure a die on thelower beam of a press brake).

The illustrated load-delivery surfaces LD of the tool holder areconfigured for engaging, and delivering force to, correspondingload-receipt surfaces LR of a tool TL. In FIGS. 14 and 15, thehorizontal load-delivery surfaces LD of the illustrated tool holder THare shown as downwardly facing surfaces, and the horizontal load-receiptsurfaces LR of the tool TL are shown as upwardly facing surfaces. Inother embodiments (e.g., where the tool holder is on a lower beam), thehorizontal load-delivery surface(s) LD of the tool holder is/areupwardly facing, and the horizontal load-receipt surface(s) of the toolis/are downwardly facing. Thus, the invention provides variouscombination embodiments wherein the shank of a tool is operativelymounted in the channel of the tool holder such that each load-deliverysurface of the tool holder is generally or substantially horizontal andis carried directly against a corresponding generally or substantiallyhorizontal load-receipt surface of the tool.

In certain embodiments, the tool holder TH is adapted for forcing a toolTL (e.g., when the tool is operatively mounted on the tool holder)against a workpiece by delivering force from the load-deliverysurface(s) LD of the tool holder to the load-receipt surface(s) LR ofthe tool. In preferred embodiments of this nature, the tool holder TH isadapted for moving the operatively mounted tool TL along a pressing axisPA (shown in FIG. 15), e.g., during a pressing operation. For example,the tool holder TH can optionally be adapted for moving the tool TL in apressing direction PD (shown in FIG. 14) that is generally orsubstantially normal to the load-delivering surface(s) LD of the toolholder. In preferred embodiments of this nature, each load-deliveringsurface LD of the tool holder TH is generally or substantiallyhorizontal, and the tool holder is adapted for moving the tool TL in agenerally or substantially vertical direction. For example, the toolholder can advantageously be adapted for moving the tool vertically intoand out of engagement with a workpiece WP (e.g., when the workpiece issecured in a workpiece location WL between upper and lower tables of thepress brake).

In some embodiments, the tool holder is operably coupled to a pressbrake ram that is adapted for moving the tool holder and the operativelymounted tool together so as to force the workpiece-deforming surface ofthe tool against a workpiece. Preferably, the ram (which can beincorporated into, or otherwise operably coupled with, a bed BE of thepress brake) is adapted for moving the tool holder TH and tool TLtogether in a pressing direction PD that is generally or substantiallynormal to the load-delivering surface(s) LD of the tool holder (e.g., ina vertical direction). In other embodiments, the tool holder TH is notadapted for moving the operatively mounted tool, but rather is designedfor securing the tool in a stationary position during pressingoperations.

Preferably, the tool holder TH has a closed configuration and an openconfiguration. When the tool holder TH is in its open configuration, itis possible to move the shank S of a press brake tool TL into and out ofthe tool holder's channel C. When the tool holder TH is in its closedconfiguration, the shank S of a tool TL mounted in the tool holder'schannel C is clamped securely, and held rigidly, against (at least partof) a wall CW of the tool holder.

The tool holder TH can optionally have a moveable face plate MP, jaw, orother clamp, which preferably defines at least part of one CW′ of theconfronting walls CW, CW′. When such a tool holder moves to its closedconfiguration, the moveable plate MP, jaw, etc. desirably moves (atleast in part) toward the other confronting wall CW (i.e., the “second”wall). On the other hand, when such a tool holder moves to its openconfiguration, the moveable plate MP, jaw, etc. desirably moves (atleast in part) away from the other confronting wall CW. The illustratedembodiments, for example, provide a moveable face plate MP that definesthe first wall CW′ and can be moved selectively toward or away from thetool holder block CB that defines the second wall CW. The illustratedblock CB is adapted for staying in a stationary lateral position duringmovement of the tool holder from its open configuration to its closedconfiguration, although this is not required. The moveable face platedesign described in this paragraph is merely one fashion in which thetool holder can be embodied so as to have a clamp that can be movedselectively between open and closed positions.

Preferably, the tool holder TH is adapted for moving a press brake toolTL along a pressing axis PA when the tool is operatively mounted on thetool holder. As noted above, the tool holder TH has two spaced-apartconfronting walls CW, CW′ bounding a tool-mount channel C that isconfigured for receiving a shank S of the tool TL. Preferably, the wallsCW, CW′ have (e.g., define) clamping surfaces 95 that are adapted forengaging and clamping the tool's shank S therebetween. That is, eachwall CW, CW′ preferably has at least one such clamping surface 95,although alternate embodiments involve a tool holder wherein only one ofthe walls CW, CW′ has such a clamping surface. In certain preferredembodiments, the tool holder TH also has movable seating members 50disposed on opposite sides of the tool-mount channel C. The seatingmembers 50 are adapted to engage opposite sides of the tool's shank Sand thereafter move together with the shank in a direction at leastgenerally parallel to the tool holder's pressing axis PA, e.g., inresponse to the first wall CW′ (or at least a part thereof) movingtoward the second wall CW at such time as the tool's shank is positionedin the tool-mount channel C.

Thus, when the tool holder TH closes on the shank S of a tool TL,seating members 50 preferably engage opposite sides of the tool's shankS. Once the preferred seating members 50 initially make contact with thetool's shank S, continued movement of the first wall CW′ toward thesecond wall CW causes the seating members to move (e.g., relative toportions of the tool holder that are stationary during such closingaction) together with the tool's shank in a direction at least generallyparallel to the tool holder's pressing axis PA. This movement of theseating members 50 together with the tool's shank S is referred toherein as “conjoint movement.” Preferably, the seating members 50 do notmove (at least not substantially) relative to the tool's shank S duringthis conjoint movement. In some embodiments, the conjoint movement endswhen the load-receipt surface(s) LR of the tool comes into directcontact with the corresponding load-delivery surface(s) LD of the toolholder. After such engagement of the load-bearing surfaces LD, LR of thetool and tool holder, continued movement of the first wall CW′ towardthe second wall CW causes (in certain embodiments) camming surfaces 325of the seating members 50 to continue camming with corresponding camsurfaces 25 of the tool holder, which causes the seating members (e.g.,contact surfaces 55 thereof) to slide relative to (e.g., upwardly along)the tool's shank, optionally until clamping surfaces 95 of the toolholder clamp forcibly on the tool's shank.

In some cases, the tool holder's channel C opens toward a workpiecelocation WL (shown in FIG. 6) and the tool holder TH is configured suchthat the conjoint movement of the seating members 50 and the tool'sshank S is movement away from (e.g., at least generally away from, suchas directly away from) the workpiece location. For example, when thetool holder TH is part of, and/or is on, the upper beam of the pressbrake, the conjoint movement desirably is upward vertical movement.

Preferably, when the first wall CW′ (or at least a part thereof) ismoved toward the second wall CW, a tool shank S in the channel C isengaged by seating members 50 and forced to move in a desired direction(e.g., upwardly) until the load-bearing surfaces LD, LR of the toolholder TH and tool TL come into direct contact with one another. Inother words, the tool TL preferably is fully seated as an adjunct of thetool holder's closing action. In more detail, the tool holder THpreferably comprises a load-delivery surface LD, the tool TL preferablyincludes a load-receipt surface LR, and in response to (at least partof) the first wall CW′ moving toward the second wall CW the seatingmembers 50 once engaged with the tool's shank S preferably move togetherwith the shank in a direction at least generally parallel to thepressing axis (e.g., vertically) until the load-receipt surface of thetool comes into direct contact with the load-delivery surface of thetool holder. It is to be appreciated that the tool and tool holder canoptionally each have two or more load-bearing surfaces, as discussedabove.

When the preferred seating members 50 engage the tool's shank S, theybear forcibly on the shank. The resulting normal force (which preferablyis oriented in a direction at least generally perpendicular to the toolholder's pressing axis) on the tool's shank creates a frictional forcethat is delivered from the seating members to the shank. In certainpreferred embodiments, this frictional force is greater than the weightof the tool TL. This will commonly be preferred when the tool holder ispart of, and/or is on, the upper beam of the press brake. In suchembodiments, the tool will be lifted toward its seated position as aresult of (optionally due only to) the frictional force.

In embodiments involving two seating members 50 disposed on oppositesides of the tool-mount channel C, the seating members can be providedin various different configurations. The seating members 50, forexample, can be wedge members WM (as exemplified in FIGS. 1-7, 11, 12,14, 15, 18, 19, 22, 23, 24A, 24B, 25-28, 30A, 30B, and 32-36) and/or rodmembers RM (as exemplified in FIGS. 16, 17, 20, and 21). Other seatingmember configurations can also be used. Moreover, the invention providescertain embodiments wherein seating members are not provided on bothsides of the channel C. Exemplary embodiments of this nature are perhapsbest appreciated in FIG. 19 (of which more will be said later).

In the illustrated embodiments, each seating member 50 preferably has acontact surface 55 that is both at least generally planar and adapted toremain oriented at least generally perpendicular to a load-deliverysurface LD of the tool holder TH during (and optionally throughout)movement of the first wall CW′ toward the second wall CW. This isperhaps best appreciated with reference to FIGS. 14 and 15. Here, it canbe appreciated that the contact surfaces 55 of the illustrated seatingmembers 50 are (e.g., when the tool holder is in its open configuration,when the tool holder is in its closed configuration, and during movementof the tool holder between these two configurations) at least generallyparallel (and preferably substantially parallel) to the clampingsurfaces 95 of the tool holder TH. This, however is not strictlyrequired.

In one group of embodiments, each seating member 50 has a contactsurface 55 that is vertical, and the tool holder TH includes two seatingmembers 50 mounted on the tool holder TH such that their verticalcontact surfaces 55 are confronting surfaces adapted for respectivelyengaging opposed vertical side surfaces 85 of the tool's shank S (here,the surfaces 85 in some cases are parallel to each other). In this groupof embodiments, the conjoint movement of the seating members 50 and thetool's shank S preferably is caused by the seating members' confrontingvertical contact surfaces 50 delivering frictional force to the opposedvertical side surfaces 85 of the tool's shank. In certain embodiments ofthis nature, the frictional force is an upward vertical force. Thisforce can optionally be the only upward vertical force applied by thetool holder (or at least by the seating members) to the tool when thewalls CW, CW′ close on the tool's shank S. In some cases, the onlyengagement of the seating members 50 and the tool's shank S involvesvertical surfaces of the seating members engaging vertical surfaces ofthe tool's shank and delivering to the shank a frictional force thatlifts the tool in an upward vertical direction until the load-bearingsurfaces LD, LR of the tool holder TH and tool TL come into directcontact with one another.

As is perhaps best appreciated with reference to FIGS. 14 and 15, theseating members 50 preferably are adapted to bear against, and cam with,respective cam surfaces 25 of the tool holder TH (e.g., in response tothe walls CW, CW′ of the tool holder closing on the tool's shank and/orduring the conjoint movement of the seating members and the tool'sshank). In some embodiments, each cam surface 25 is defined by a slanted(e.g., with respect to the pressing axis PA, which optionally is avertical axis) and/or curved wall section of the tool holder. Forexample, each of the illustrated cam surfaces 25 is defined by a slanted(e.g., with respect to the tool holder's clamping surfaces 95) wallsection. The angle at which each cam surface 25 is offset from verticalcan be varied as desired. In one useful example, this angle is about 13degrees. In some cases, the confronting cam surfaces 25 diverge awayfrom each other with increasing distance from a workpiece location WL(see FIG. 6).

In FIGS. 14-15 and 16-17, first and second seating members 50 aremounted respectively on the first CW′ and second CW walls of the toolholder TH. Preferably, each seating member 50 has some freedom to moverelative to the wall on which it is mounted. For example, the firstseating member can be mounted on the first wall CW′ so as to have adesired range of freedom to move (e.g., vertically and/or horizontally)relative to the first wall, and the second seating member can be mountedon the second wall CW so as to have a desired range of freedom to move(e.g., vertically and/or horizontally) relative to the second wall. Insome embodiments of this nature, the first wall CW′ is laterallymoveable (at least in part) selectively toward or away from the secondwall CW, and the second wall CW is adapted to be retained in astationary lateral position (e.g., during the closing action of the toolholder TH and/or during the conjoint movement of the seating members 50and the tool's shank S). The features described in this paragraph,however, are not strictly required.

Preferably, each seating member 50 is mounted on the tool holder TH soas to be moveable between first and second positions. In some preferredembodiments of this nature, the tool-mount channel C opens toward aworkpiece location WL, and each seating member 50 when in the firstposition is closer to the workpiece location than when in the secondposition. Preferably, movement between the first and second positionsinvolves the seating member 50 undergoing a change in vertical position(i.e., elevation), e.g., relative to a portion of the tool holder thatis stationary during the tool holder's closing action and/or during theconjoint movement of the seating members and the tool's shank.

FIG. 14 depicts the first position for two exemplary seating members 50.The illustrated seating members 50 occupy their first position prior tobeing moved into forcible engagement with the tool's shank. The firstposition here occurs when each seating member is at the lowest elevationin its range of motion. FIG. 15 depicts the second position for two suchseating members 50. Here, each seating member ends up being in itssecond position once the tool holder has fully closed on the tool'sshank. Thus, the second position here occurs when each seating member isat a higher elevation than when in the first position (optionally thesecond position is the highest elevation the seating member occupiesduring, or at the conclusion of, the tool holder's closing action uponthe shank of a tool). These features, however, are by no means required.In some embodiments, once the tool holder has fully closed on a tool'sshank, the seating members no longer hold the tool in position, butrather all the clamping force on the tool at such time can optionally beprovided by the tool holder's clamping surfaces 95.

The seating members 50 can be mounted on the tool holder TH in differentways. In some cases, the first seating member 50 is mounted on the toolholder TH such that at least a portion of this seating member ismoveable between first and second positions by sliding along a slantedfirst cam surface 25 of the tool holder. Additionally or alternatively,the second seating member 50 can be mounted on the tool holder such thatat least a portion of this seating member is moveable between first andsecond positions by sliding along a slanted second cam surface 25 of thetool holder. In some embodiments of this nature, the tool-mount channelC opens toward a workpiece location WL, and the first and second slantedcam surfaces 25 diverge away from each other with increasing distancefrom the workpiece location. This is best seen in FIG. 6.

In embodiments where the seating members 50 are mounted on the toolholder TH so as to be moveable between first and second positions, eachseating member can optionally be resiliently biased toward its firstposition. With reference to FIG. 7, it can be appreciated that a springmember 200 can be provided to resiliently bias each seating member 50toward its first position. Here, each spring member 200 is mounted in abore 200B defined by the tool holder TH such that each spring member iscompressed between a seating member 50 and a surface 200S of the toolholder. In embodiments like that of FIG. 22, each spring member can bemounted in a bore 200B′ defined by a seating member 50. Here, eachspring member (not shown) is compressed between a seating member 50 anda surface 200S of the tool holder. Thus, one end of each spring member200 seats against a surface 200S of the tool holder TH, while the otherend seats against a seating member 50. As a result, each seating member50 is resiliently biased toward its first position. In embodiments likethat of FIG. 24A, each spring member 200 is a retaining spring thatholds a seating member 50 in place and resiliently biases it toward itsfirst position.

In FIG. 7, respective stop surfaces 50S and 60S of the seating member 50and tool holder TH are shown as being separated for illustrationpurposes. It will be appreciated, though, that each spring member 200would normally keep such surfaces together by holding each seatingmember 50 in the first position (i.e., until the tool holder is clampedon a tool so as to move each seating member to the second position, inthe process overcoming the force of each spring 200).

In certain preferred embodiments, at least part of at least one of theseating members 50 has a cross-sectional configuration that is at leastgenerally triangular. FIGS. 11 and 12 exemplify one useful seatingmember 50 of this nature. Here, the seating member 50 has a head portion59 and a neck portion 56. The illustrated head portion 59 has agenerally triangular cross-section (taken along a plane lying in boththe “x” axis and the “y” axis). In other embodiments, there is provideda seating member 50 that does not have an elongated neck portion butdoes have a cross-sectional configuration that is at least generallytriangular. Reference is made to FIGS. 24A and 24B.

One group of embodiments provides a seating member having a cammingsurface 325 that is oblique to (perhaps being offset by at least 5degrees from) the contact surface 55 of the seating member. Here, duringconjoint movement of the tool and the seating member, the contactsurface 55 desirably is directly engaged with (and preferably does notmove relative to) the tool, while the camming surface 325 of the seatingmember cams with a corresponding cam surface 25 of the tool holder. Manyadvantageous embodiments of this nature can be provided.

The seating member assembly shown, for example, in FIGS. 1 and 7, isrepresentative of a group of embodiments wherein each seating member ismounted removably on the tool holder. Here, the neck 56 of the seatingmember 50 defines a groove 50G that is adapted for removably receiving afastener 170. The optional fastener can be a clip (as exemplified inFIG. 13), pin, or another removable fastener. Thus, in certainembodiments, each seating member is mounted on the tool holder by virtueof a removable fastener, such that a damaged seating member can beeasily removed and replaced. In some embodiments, a removable seatingmember comprising (optionally formed of) polymer is provided.

With reference to FIGS. 3, 6, 7, and 9, one exemplary seating memberdesign comprises a wedge/clip assembly. Here, the seating member 50 is awedge member of the type exemplified in FIGS. 11 and 12, and thefastener 170 is a clip of the type exemplified in FIG. 13. In FIGS. 7and 9, it can be seen that the neck 56 of each wedge member extendsthrough an opening 510 in one of the tool holder's confronting walls CW,CW′. Each illustrated opening 510 extends laterally through the entirethickness of the wall. The opening 510 is vertically elongated so thatthe neck 56 of the seating member has a range of freedom to movevertically within the opening 510. The head 59 of the wedge member islarger than the opening 510, such that the head 59 is not able to passthrough the opening 510. The neck 56 of the wedge member has an endregion that projects out from one end of the opening 510, and this endregion has therein formed a groove 50G in which the clip 170 isremovably retained. Thus, the neck 56 of the wedge member is retained inthe opening 510 by virtue of the head 59 and clip 170 serving as stopsthat prevent the wedge member from escaping the opening 510. This typeof wedge/clip assembly is merely one example of a suitable seatingmember design. Many useful variants will be apparent to skilled artisansgiven the present teaching as a guide. Moreover, a wedge member of thisnature may be used advantageously without providing the clip member.

One manner of assembling a resiliently-biased wedge/clip assembly can beappreciated by referring to FIGS. 1 and 7. Here, each spring 200 isinserted into an opening 710 of each vertical bore 200B. The spring 200is positioned against surface 200S and compressed such that the springdoes not prevent the neck 56 of the wedge member from being insertedinto one end of the lateral opening 510 and advanced laterally throughthe opening 510 so that the end region of the neck 56 projects out fromthe other end of the opening 510. Once the neck 56 of the wedge memberis inserted into, and advanced through, the opening 510, the clip 170 isfastened in the wedge members grove 50G so that the wedge member isprevented from coming off the wall on which it is mounted. It is to beappreciated that the features described in this paragraph merely reflectone exemplary manner of assembling a resiliently-biased seating memberon the tool holder. Many different alternatives can be used. Forexample, the configuration shown can also be used by simply omitting theclip 170.

In one group of embodiments, at least one of the seating members 50comprises a wedge member at least a portion of which is carriedalongside a cam surface 25 of the tool holder. Preferably, the camsurface 25 is adapted to bear against, and cam with, the wedge member(e.g., a camming surface 325 thereof) so as to cause relative movementof the wedge member and the cam surface. In some embodiments of thisnature, the wedge member is mounted on the tool holder so as to bemoveable between first and second positions. The wedge member, forexample, can be moveable between first and second positions by virtue ofthe wedge member (or at least a portion thereof) sliding along the camsurface 25. This is perhaps best appreciated with reference to FIGS. 14and 15.

The cam surface 25 can optionally be defined by a slanted and/or curvedwall section of the tool holder. In FIGS. 14 and 15, the cam surface 25is defined by a slanted wall section, although this is not required. Theslanted wall section extends between two projections 90 of thisillustrated tool holder. Each of these projections 90 defines a clampingsurface 95 (i.e., a surface that engages and forcibly retains the tool'sshank when clamped in an operative position on the tool holder). Thus,the cam surface (which can optionally be a slanted and/or curved wallsection) 25 together with the two projections 90 define a recess 70 inwhich at least part of the wedge member is disposed. These optionalfeatures, however, are not required.

In the embodiments of FIGS. 14 and 15, it is preferable that at leastpart of the wedge member project out of the recess 70 laterally beyondthe projections 90 when the wedge member is in its first position.Further, when the illustrated wedge member is in its second position, itpreferably does not project laterally beyond the projections 90. This isperhaps best appreciated by comparing FIG. 14 (in which each wedgemember projects laterally beyond both of the two adjacent projections)and FIG. 15 (in which each wedge member does not project laterallybeyond either of the two adjacent projections).

With continued reference to FIGS. 14 and 15, both of the illustratedseating members 50 comprise (e.g., are) wedge members that are adaptedto bear against, and cam with, respective cam surfaces 25 of the toolholder TH. In more detail, when the first wall CW′ is moved toward thesecond wall CW (i.e., at such time as the shank of a tool is received inthe tool holder's channel), the wedge members forcibly sandwich thetool's shank S and in the process deliver frictional force to the shank.Preferably, this frictional force is oriented in a direction at leastgenerally parallel to the pressing axis PA and causes the tool's shank Sto move (together with the wedge members) relative to the cam surfaces25 (and/or to the clamping surfaces as) until a load-receipt surface LRof the tool TL engages a load-delivery surface LD the tool holder TH.

As is perhaps best seen in FIG. 1, a plurality (e.g., a series) ofseating members 50 can optionally be mounted along a longitudinal lengthof the tool holder's first wall CW′. Here, a horizontal row ofindividual (e.g., discrete) seating members 50 are provided along thetool holder's first wall CW. Additionally or alternatively, a pluralityof seating members 50 can optionally mounted (e.g., in a horizontal row)along a longitudinal length of the tool holder's second wall CW′. Inother embodiments, the tool holder can simply have two seating membersdisposed on opposite sides of the tool-mount channel. Further, theinvention provides some embodiments where seating members are notprovided on both sides of the channel C. Reference is made to FIG. 19.Thus, the number of seating members, and their arrangement on the toolholder, can be varied to meet the requirements of differentapplications.

As noted above, the tool holder TH preferably has a closed configuration(exemplified in FIGS. 6, 7, 15, and 17-19) and an open configuration(exemplified in FIGS. 1, 4, 5, 16, 20, and 21). In such embodiments, thefirst CW′ and second CW confronting walls preferably are closer together(at least in part) when the tool holder TH is in its closedconfiguration than when the tool holder is in its open configuration. Incertain embodiments of this nature, the tool holder TH is resilientlybiased toward its closed configuration. For example, one or more springmembers SP can optionally be used to resiliently bias the tool holder THtoward its closed configuration. In some cases, springs or otherresilient means are provided for biasing the tool holder toward itsclosed configuration and the tool holder has a selectively-operableactuator A adapted for being operated at a desired time to move the toolholder from its closed configuration to its open configuration. Incertain embodiments of this nature, the actuator A is a hydraulicactuator, and the tool holder TH is resiliently biased toward its closedconfiguration by at least one spring member SP.

In other embodiments, the tool holder is resiliently biased toward itsopen configuration, such as by one or more spring members SP′. Exemplaryembodiments of this nature (see FIGS. 26, 27 and 30-36) involve springsSP′ or other resilient means for biasing the tool holder toward its openconfiguration and a selectively-operable actuator A adapted for beingoperated at a desired time to move the tool holder from its openconfiguration to its closed configuration. In embodiments like thoseexemplified in FIGS. 26, 27 and 30-36, the actuator A is hydraulic, andthe tool holder is resiliently biased toward its open position by atleast one spring member SP′.

When provided, the hydraulic actuator can advantageously comprise ahydraulic line HL at least a length of which is defined by a block CB ofthe tool holder. In some embodiments, this block CB also defines atleast part of one of the confronting walls CW, CW′ of the tool holderTH. Hydraulic fluid will generally (e.g., during use) be disposed withinthe hydraulic line HL, the block CB will commonly be a piece of metal(e.g., steel, such as 2312 prehard steel as is available commerciallyfrom Thyssen Krupp, Düsseldorf, Germany), and the hydraulic fluid canadvantageously be in direct contact with an inner surface HLS of thehydraulic line length that is defined by the block CB (e.g., such thatthis inner surface HLS is defined by the metal of the block CB). Theseoptional features can be provided, for example, in embodiments wherein ahydraulic actuator is built directly into (e.g., a block CB of) the toolholder TH.

FIGS. 3-5 detail an embodiment wherein the tool holder is resilientlybiased toward its closed configuration and a hydraulic actuator isprovided for moving the tool holder to its open configuration. Here, aface plate MP (optionally formed of steel, such as the 2312 prehardsteel available commercially from Thyssen Krupp) is mounted on the toolholder TH for lateral movement between open and closed positions. Themoveable plate MP is mounted to a block CB of the tool holder TH by aplurality of bolts 20 each anchored at one end to the block CB. Theillustrated block CB is adapted for being retained in a stationarylateral position during movement of the plate MP toward the block CB,although this is not required. Each bolt 20 has a neck 24 and a head 28.The neck 24 defines the anchored end of the bolt. The neck 24 extendsaway from the block CB and to the head 28 of the bolt. The moveableplate MP has a plurality of lateral openings 210 (further exemplified inFIGS. 9 and 10) through each of which the neck 24 of a bolt 20 projects.The plate MP is adapted to slide laterally on the necks 24 of the bolts20 when the tool holder TH is moved between its open and closedconfigurations. The head 28 of each bolt 20 (optionally together with awasher WA) is sufficiently large (e.g., larger than opening 210) toprevent the plate MP from coming off the bolt. A spring member(optionally a spring washer) SP is positioned between the head 28 ofeach bolt 20 and the moveable plate MP. Such spring members SPresiliently bias the plate MP toward the block CB. As shown in FIGS.1-3, the moveable plate MP can optionally be mounted on the tool holderTH by a plurality of bolt/spring assemblies of the described nature.

An advantageous fail-safe capability can be achieved by providing ahydraulic actuator (or another selectively-operable actuator) incombination with a clamp that is resiliently biased toward its closedposition. This combination assures that the tool holder will move to, orstay in, its closed configuration in the event of any loss of power tothe press brake. Thus, any tools mounted on the tool holder will remainsecurely clamped in the event of power loss. A variety ofselectively-operable actuators can be used in such fail-safeembodiments. Likewise, a variety of spring means can be used toresiliently bias the tool holder toward its closed configuration.

FIG. 4 details one exemplary manner in which a hydraulic actuator can beused. Here, the hydraulic actuator A is built into the tool holder blockCB. In more detail, the block CB itself defines an internal hydraulicline HL. To operate the actuator A, hydraulic fluid (e.g., pressurizedoil) is delivered through the hydraulic line HL into an internalhydraulic reservoir 145, which preferably is also defined by the blockCB. The hydraulic fluid delivered to the reservoir 145 applies pressureto a surface 147 of a cylinder or another moveable body 140, therebyforcing the body 140 to move from a retracted position to an extendedposition, in the process bearing against the moveable face plate MP andcausing it to move from its closed position to its open position. Inmore detail, delivering hydraulic fluid into the reservoir 145 causesthe body 140 to move (e.g., within an opening 143 defined by the blockCB) in such a way that a leading surface 142 of the body 140 bearsforcibly against the plate MP, hence causing the plate MP to move awayfrom the block CB. O-rings 144 and/or backer seals or the like arepreferably provided to create a substantially fluid-tight seal betweenthe moveable body (e.g., cylinder) 140 and the block CB.

With reference to FIGS. 3-5, it can be appreciated that the illustratedface plate is operably coupled with a plurality of hydraulic actuatorsand a plurality of bolt/spring assemblies (described above). In FIGS.3-5, the hydraulic actuators and bolt/spring assemblies are spacedalternately along a longitudinal length of the face plate. Thisarrangement, however, is strictly optional.

In FIGS. 26, 27, and 30-36, another advantageous manner of employing ahydraulic actuator A is shown. Here again, the hydraulic actuator A isbuilt into (i.e., is internal to) the tool holder block CB. Thus, theblock CB itself defines an internal hydraulic line HL. The tool holderhas a face plate MP that is maintained in its open position by at leastone spring member SP′. The spring member SP′, for example, can be seatedin a pocket defined by the tool holder block CB (see FIGS. 26 and 33)such that the spring SP′ (preferably together with a plurality of othersprings SP′ similarly arranged at locations spaced along a length of thetool holder) bears resiliently against the face plate MP so as to biasthe plate MP toward its open position. When the actuator A is actuated,hydraulic fluid is delivered through the hydraulic line HL (see FIGS. 27and 31) into an internal hydraulic reservoir 145, which preferably isalso defined by the tool holder block CB. The hydraulic fluid deliveredto the reservoir 145 applies pressure to a surface 147 of a cylinder oranother moveable body 140, thereby forcing the body 140 to move in sucha way (to the right as seen in FIG. 27, to the left as seen in FIG. 31)that the face plate MP is forced to move toward to tool holder block CB(such as by virtue of the rod end RE of the moveable body 140 having anut 803 and washer 804 that bear forcibly against a surface 807 of theface plate). O-rings, backer seals, and/or other hydraulic sealingcomponents can be provided as needed.

In embodiments involving a tool holder with a moveable plate MP or otherclamp resiliently biased (e.g., by a plurality of springs SP′) toward anopen position in combination with a hydraulic actuator (or anotherselectively-operable actuator) adapted for being actuated so as to movethe tool holder to its closed position (e.g., in the process overcomingthe force of the springs SP′), an advantageous fail-safe capability canbe provided by using a hydraulic system with a check valve. The checkvalve, when provided, is adapted to stop backflow of hydraulic fluid inthe system. Thus, if the tool holder is in its closed position (andclamped forcibly on the shank of a tool) at such time as a loss of poweroccurs, the check valve will prevent hydraulic fluid backflow, whichwould otherwise allow the tool holder to move to its open position (dueto the resilient bias of the springs SP′). As a result, the tool holderwill stay in a closed position if power goes out at a time when one ormore tools are operably clamped on the tool holder. Thus, thecombination of a mechanical (e.g., spring based) constant-bias openingsystem and a selectively-operable hydraulic closing system with a checkvalue (or other device adapted to prevent hydraulic fluid backflow) canbe particularly advantageous.

In certain embodiments, the tool holder comprises a block CB, optionallycomprising an integral piece of metal, having a longitudinal length ofat least 1 foot, at least 1.5 feet, or even 2 feet or more. Inembodiments of this nature, the tool holder can optionally includes amoveable plate MP, optionally comprising an integral piece of metal,that extends along a major portion (50% or more) of the block's length,or extends along substantially the entire length of the block, orextends along the entire length of the block.

In certain embodiments, the tool holder TH includes a plurality ofsections connected in series by their longitudinal ends. FIG. 25 showsone longitudinal end of a tool holder section. Reference is also made toFIGS. 30A, 30B, 35, and 36. Two blind bores DW are provided on each endas dowel seats. Thus, when it is desired to connect a first section witha second section, two dowels DS (see FIGS. 30 and 30B) extending fromthe first section can be fitted respectively in two dowels seats on thesecond section, whereafter two dowels on another end of the secondsection can be fitted respectively in two dowel seats on an end of athird section, and so on. An optional through-port connector THC can beprovided to connect the hydraulic lines HL of the serially connectedsections of the tool holder. The connector, when provided, can also helpassure proper alignment of the tool holder sections. In embodimentsinvolving serially connected sections of a tool holder with hydraulicactuation, it may be advantageous to provide a strap STR or otherconnector that prevents the hydraulic pressure within themultiple-section tool holder from forcing the connected sections apart.A strap, clip, or the like (e.g., of metal) connected rigidly to theadjacent ends of two sections can be used.

In certain embodiments, it can be advantageous to provide a constantupward bias on the face plate MP. This, for example, can help assureproper alignment of seating members 50 on opposite sides of thetool-mount channel C. Exemplary embodiments are shown in FIGS. 28 and34-36. Here, a spring-biased bearing member BM applies an upward forceto the face plate MP by bearing forcibly against an angled surface CS ofthe face plate MP. In the illustrated design, this keeps a planar topsurface TS of the plate MP snuggly against a planar, downwardly-facingsurface 409 of the tool holder block CB, which thereby assures properpositioning and alignment of the seating members 50. In this design, thesurfaces TS, 409 slide against each other during opening and closing ofthe tool holder. These details, however, are strictly optional.

One particular embodiment of the nature depicted in FIGS. 26-28 and30-36 will now be described. The tool holder includes a plurality ofsections connected in series as described above. The operating hydraulicpressure is about 3,000-4,000 psi. Each section of the tool holder isabout two feet long. Six hydraulic pistons (as moveable bodies 140) arespaced along the length of each section every 4½ inches or so. Twospring biased bearing members BM (see FIGS. 28, 34, and 36) are providedon each section. The bearing members are formed of steel, and they areeach biased by a heavy die spring (450 pounds). Three springs SP′ of thenature described above (and shown in FIGS. 26 and 33) are also provided.Each spring SP′ is a medium die spring (250 pounds). All surfaces of thetool holder block CB (except the internal walls of the hydraulic linesHL through which the hydraulic fluid flows), and all surfaces of theface plate MP, are nitrided. Each seating member 50 is a wedge member ofnylon 66 with 20% glass filler. These exemplary features, of course, areby no means required or limiting to the invention.

FIGS. 22 and 23 depict one of the embodiments wherein the tool holder THincludes seating members 50 on both sides of the tool-mount channel C.Here, the seating members are pin-like wedge members. In thisembodiment, each wedge member (or “lifting wedge”) WM has a cammingsurface 325 that is adapted to cam with a corresponding cam surface 25of the tool holder TH. Here, the cam surfaces 25 are defined byretaining wedges RW adjacent to respective ones of the wedge members WM.Each cam surface 25, 325 is at an oblique angle relative to the contactsurfaces 55 of the wedge members WM (and relative to clamping surface 95of the tool holder). Thus, when the shank of a tool is positioned in thetool-mount channel C and the moveable plate MP is moved toward the toolholder block CB (so as to close the wedge members WM on opposite sidesof the tool's shank), each retaining wedge RW forces a wedge member WMto undergo a camming action with such retaining wedge. This cammingaction involves each wedge member WM moving to a higher elevationconjointly with the tool. In more detail, as the contact surfaces 55 ofthe wedge members 50 close upon the tool's shank, the cam surfaces 25 ofthe retaining wedges RW bear forcibly against the respective cammingsurfaces 325 of the wedge members WM. As the moveable plate MP continuesmoving closer to the tool holder block CB, each pair of these engagedsurfaces 25, 325 cam with each other. This causes the lifting wedges WMto move upwardly (together with the tool) relative to the tool holderblock CB. This provides the desired tool seating functionality wherebysimply closing the tool holder on the shank of a tool results in thetool being operably seated in the tool holder (such that theload-delivering surface(s) of the tool holder is/are engaged withcorresponding load-receiving surface(s) of the tool). Due to the limitedfreedom of movement of the lifting wedges WM in the bore 510 (as well asthe restrictive mechanical coupling of each lifting wedge WM with itscorresponding retaining wedge RW), the occurrence of any rocking of thewedge members WM is minimized or eliminated during use. In FIGS. 22 and23, each lifting wedge WM actually has two camming surfaces 325, 225adapted respectively to cam with two corresponding cam surfaces 25, 425of a retaining wedge RW. In another embodiment, the separate retainingwedges are eliminated by forming the tool holder block CB and themoveable plate MP so that integral parts of these bodies CB, MP definethe same cam surfaces 25, 425 as the retaining wedges RW in FIGS. 22 and23.

In FIGS. 22 and 23, the contact surface 55 of each wedge member WM has acircular shape (see FIG. 23). This is by no means required. However,providing the wedge members in the form of pin-like bodies can beadvantageous. For example, each pin-like wedge member WM in FIGS. 22 and23 has a leading portion 50LP with a cross section that is circular.This can be advantageous in that the openings 510 can be formed ascylindrical bores.

In other embodiments, though, each seating member 50 is a wedge memberWM with a leading portion having a rectangular cross section. Referenceis made to FIG. 11.

FIGS. 16 and 17 depict embodiments wherein the tool holder TH isprovided with seating members 50 that comprise (e.g., are) rod membersRM. Each illustrated rod member RM is moveable between first and secondpositions. Preferably, each rod member RM is resiliently biased towardsits first position by a spring member 300. FIG. 17 depicts one manner inwhich spring members 300 can be used to resiliently bias such rodmembers RM. Here, each rod member RM is mounted in a bore 305 so as tobe slidable (e.g., axially) between first and second positions. In theembodiment of FIG. 17, each bore 305 is a blind opening defined by thetool holder TH, although this is not required. A spring 300 ispositioned between the rear end 52 of each illustrated rod member and atool holder surface 308. In FIG. 17, this surface 308 defines the blindend of the bore 305.

With continued reference to FIGS. 16 and 17, each rod member RM has acontact surface 55 that is adapted to engage the shank of a tool. Whenthe tool's shank is positioned in the channel C and the first wall CW′is initially moved toward the second wall CW, the rod members RM arepressed against the tool's shank due to the bias of the springs 300.Thereafter, as the first wall CW′ continues moving closer to the secondwall CW, the rod members RM are prevented from moving relative to thetool's shank by friction between the contact surfaces 55 and the tool'sshank. This continued movement of the first wall CW′ toward the secondwall CW results in the rod members being forced further into theirrespective bores 305. As the rod members RM retract further into thebores 305, the tool's shank moves conjointly with the rod members untileach load-receipt surface of the tool comes into direct contact with aload-delivery surface of the tool holder. At this point, engagement ofthe load-bearing surfaces of the tool and tool holder prevents furtherconjoint movement of the rod members and the tool's shank. Continuedmovement of the first wall CW′ toward the second wall CW preferablycauses the rod members RM to retract even further into the bores 305until the tool holder's clamping surfaces 95 come to bear fully uponopposite sides of the tool's shank. At this point, the tool is rigidlyclamped in its operative position.

Embodiments have been described wherein the tool holder includesconfronting wedge members. Embodiments have also been described whereinthe tool holder includes confronting rod members. In other embodiments,a wheel member WH is provided on one of the confronting walls, while awedge member or rod member is provided on the other confronting wall.Reference is made to FIGS. 18 and 20. The wedge member or rod member candeliver frictional force to one side of a tool's shank such that thetool is moved (e.g., upwardly) in the tool-mount channel. As the toolmoves in this manner, the other side of its shank can ride along therotating wheel member WH until the tool reaches its fully seatedposition. Embodiments of this nature can involve a plurality of wheelmembers positioned along one of the confronting walls, while the otherconfronting wall can have a plurality of wedge members and/or rodmembers. Each wheel member WH, when provided, preferably retracts(optionally overcoming the resilient bias of one or more springs) intoan opening in the tool holder when the first and second walls clampfully upon the shank of a tool.

Thus, the tool holder TH can be provided with one or more seatingmembers 50 of various different designs. In one group of embodiments,the tool holder includes at least one seating member having at least onepart (optionally the whole seating member) comprising (optionallyconsisting essentially of) a polymer, optionally together with a filler.One useful polymer is nylon, such as nylon 66. Torlon or ultra highmolecular weight polyethylene may also be suitable. If so desired, thepolymer can comprise a filler to provide increased hardness, increaseddurability, and/or decreased flexibility. Glass fibers are anadvantageous filler (e.g., nylon 66 with 20% glass filler has given goodresults). Other useful fillers may include fumed silica or talc.

The invention provides a group of embodiments wherein the seatingmembers 50 are formed of one material while the tool holder block CBand/or the face plate MP (when provided) are formed of another(different) material. The block CB and/or the face plate MP, forexample, can comprise (e.g., consist essentially of) metal (e.g., steel)while the seating members 50 can comprise (e.g., consist essentially of)a polymer, optionally together with a filler. Thus, the contact surfaces55 (which preferably directly contact, and lift, the tool when the toolholder closes on the tool's shank) of one or more seating members 50 onthe tool holder can optionally be defined by a polymer.

In one group of embodiments, the tool holder TH is provided with atleast one coating over at least one surface. In some embodiments of thepresent group, a coating is provided on one or more (optionally on each)of the tool holder's clamping surfaces 95. Additionally oralternatively, a coating can be provided over a surface 409 of the toolholder block CB, and this surface 409 is one that slides relative to acoated surface TS of the face plate MP during the closing and openingaction of the tool holder. In some preferred embodiments, the toolholder block CB and/or the face plate MP are provided with a coatingover at least a majority of the surface area (optimally over all surfacearea except those surfaces defining any internal hydraulic lines throughwhich hydraulic fluid may flow). The coating can be provided to increasesurface hardness, to increase lubricity, and/or to otherwise protectagainst wear, corrosion, sticking, and/or galling.

When provided, the coating can optionally be a dry lubricant coating.For example, the coating can comprise nickel (e.g., nickel alloy) and/ora low friction polymer. In some cases, the coated surface has one ormore of the following features: (i) a coefficient of static frictionbelow 0.35, below 0.3, or even below 0.2; (ii) a coefficient of dynamicfriction below 0.3, below 0.25, below 0.18, or even below 0.1. Suitabledry lubricant coatings are available commercially from, for example,General Magnaplate Corporation (Linden, N.J., USA) and PoetonIndustries, Ltd. (Gloucester, England). As one example, the coating canbe a NEDOX® coating.

In one subgroup of the present embodiments, the coating comprises anitride and/or a carbide. One commercially available nitride coating isthe Nitrex® coating, which is a high endurance surface enhancementavailable commercially from Nitrex, Inc. (Aurora, Ill., USA).Particularly useful nitriding and nitrocarburizing enhancements aredescribed in U.S. Pat. No. 6,327,884, the entire teachings of which areincorporated herein by reference.

Nitriding and nitrocarburizing processes are known in the field and neednot be described in great detail. Reference is made to U.S. Pat. Nos.4,790,888 and 4,268,323, the salient teachings of which regarding suchenhancements are incorporated herein by reference. The latter patentrefers to the use of a fused salt bath to enable nitrogen and carbon todiffuse into the surface of a steel piece suspended in the bath to forma carbonitride case. Reference is made also to U.S. Pat. No. 5,234,721(referring to methods of forming carbonitride coatings), the salientteachings of which regarding such coatings are incorporated herein byreference.

Nitriding processes, both plasma (ion) nitriding and liquid nitriding,are described in detail in the ASM Handbook prepared under the directionof the ASM International Handbook Committee, Revised vol. 4: HeatTreating, pp. 410-424 (1994), the relevant teachings of which concerningnitriding enhancements are incorporated herein by reference. Plasma orion nitriding involves the use of glow discharge technology to providenascent nitrogen to the surface of a heated steel part. Here, the partis subjected to a nitrogen plasma in a vacuum chamber. Nascent nitrogendiffuses into the surface of the part to form an outer “compound” zonecontaining γ (Fe₄N) and ε (Fe_(2,3)N) intermetallics, and an inner“diffusion” zone which may be described as the original coremicrostructure with some solid solution and precipitation strengthening.Liquid nitriding involves immersing a steel part in a molten,nitrogen-containing fused salt bath containing cyanides or cyanates,e.g., NaCN or NaCNO. Tool components can be enhanced by liquid nitridingthrough a wide variety of commercial coating manufacturers, such asMetal Treaters Inc. of St. Paul, Minn., USA.

In some embodiments, the tool holder is adapted for use with a toolhaving a shank one side of which is provided with one or more wheelmembers. The tool holder in these embodiments can have one or more wedgemembers and/or rod members on one of the confronting walls, while theother confronting wall has no seating members. Reference is made to FIG.19. The one or more wedge members and/or rod members can deliverfrictional force to one side of the tool's shank such that the tool ismoved (e.g., upwardly) in the tool-mount channel, and as the tool movesin this manner the wheel member(s) on the other side of the tool's shankcan ride along the confronting wall that is devoid of seating membersuntil the tool reaches its fully seated position. In embodiments of thisnature, each wheel member preferably retracts (optionally overcoming theresilient bias of one or more springs) into an opening in the tool whenthe first and second walls of the tool holder clamp fully upon the shankof the tool.

In certain embodiments, the tool holder TH includes an actuator A thatis hydraulic. In some of these embodiments, the tool holder TH includesa hydraulic line HL, optionally provided in the form of a bore extendingthrough the body (e.g., a block CB) of the tool holder. In some cases,the hydraulic line HL is adapted for use at pressures in excess of about1,000 psi, such as between about 1,000 psi and about 5,000 psi, andperhaps optimally between about 3,500 psi and about 5,000 psi (or3,000-4,000 psi). In certain related method embodiments, the methodcomprises delivering hydraulic fluid pressurized at 1,000 psi or morethrough the hydraulic line HL and into a hydraulic reservoir 145 of thetool holder TH, with the result that the tool holder is actuated (e.g.,moved to its open configuration or to its closed configuration).

In certain embodiments, the invention provides methods of operating apress brake. For example, certain embodiments provide a method ofmounting a press brake tool on a tool holder having a tool-mount channelbounded by two spaced-apart confronting walls. In some of theseembodiments, the confronting walls have clamping surfaces for engagingand clamping a shank of the tool therebetween as a first of the walls ismoved toward a second of the walls. Preferably, the tool holder TH isadapted for moving the tool TL when operatively mounted on the toolholder along a pressing axis PA. In the present method, the tool holderhas confronting movable seating members 50 disposed on opposite sides ofthe tool-mount channel C. The method comprises positioning the tool'sshank S in the tool-mount channel C, moving the first wall CW′ towardthe second wall CW such that the seating members 50 engage oppositesides of the tool's shank, and moving the thus engaged seating memberstogether with the tool's shank in a direction (e.g., upwardly) at leastgenerally parallel to the tool holder's pressing axis PA. During thisconjoint movement of the seating members 50 and the tool's shank S, thefirst wall CW′ preferably continues moving closer to the second wall CW.In some cases, the method further comprises clamping the tool's shank Sbetween the tool holder's clamping surfaces 95 after a cessation of theconjoint movement of the seating members 50 and the tool's shank S(which cessation optionally occurs when load-bearing surfaces LD, LR ofthe tool and tool holder come into engagement). The first wall CW′optionally continues to move toward the second wall CW until theclamping surfaces 95 of the tool holder TH engage and clamp the tool'sshank S, whereupon the clamping surfaces preferably apply to the tool'sshank a force that is at least substantially perpendicular to the toolholder's pressing axis PA. In some embodiments of this nature, the forceapplied by the clamping surfaces 95 to the shank S is substantially (orentirely) devoid of a seating component directed parallel to the toolholder's pressing axis PA.

In some cases, the whole first wall CW′ is moveable toward (at leastpart of) the second wall CW during the closing action of the toolholder. In other cases, only part of the first wall (or a component thatis extendable from it) moves toward the second wall. In one example, apin or block is extendable from the first wall so as to force a tool'sshank against the second wall, which has one or more seating members(optionally lifting wedges). Other useful variants will be apparent topeople skilled in this area of technology given the present teaching asa guide. Thus, the first wall of the tool holder can be moved toward thesecond wall in different ways, i.e., the whole wall can move, part ofthe wall can move, a component extendable from the first wall can move,etc.

In some embodiments of the present method, the tool-mount channel Copens toward a workpiece location WL, and the conjoint movement of theseating members 50 and the tool shank's S is directed away from theworkpiece location.

In certain embodiments, the tool holder TH comprises a load-deliverysurface LD, the tool TL includes a load-receipt surface LR, and themovement of the first wall CW′ toward the second wall CW causes theseating members 50 once engaged with the tool's shank S to move togetherwith the shank in the desired direction (which is at least generallyparallel, and preferably is substantially parallel, to the pressingaxis) until the load-receipt surface of the tool comes into directcontact with the load-delivery surface of the tool holder. As notedabove, each seating member 50 can optionally have a contact surface 55that is at least generally planar and remains oriented at leastgenerally perpendicular to the load-delivery surface LD throughout themovement of the first wall CW′ toward the second wall CW.

Optionally, in the present method, each seating member has a verticalcontact surface and the confronting seating members are mounted on thetool holder such that their vertical contact surfaces are confrontingsurfaces that respectively engage opposed vertical side surfaces of thetool's shank during movement of the first wall toward the second wall.Here, the conjoint movement of the seating members and the tool's shankpreferably is caused by the confronting vertical contact surfacesdelivering frictional force (e.g., static frictional force) to theopposed vertical contact surfaces of the tool's shank. In someembodiments of this nature, the conjoint movement of the seating membersand the tool's shank is upward vertical movement.

Preferably, in the present method, the seating members 50 bear against,and cam with, respective cam surfaces 25 of the tool holder TH duringthe conjoint movement of the seating members and the tool's shank S.Each cam surface 25 can optionally be defined by a slanted or curvedwall section of the tool holder TH. When the seating members 50 cam withsuch surfaces, the camming involves the seating members sliding alongthe respective cam surfaces.

In certain embodiments of the present method, a first of the seatingmembers is mounted on the first confronting wall CW′, a second of theseating members is mounted on the second confronting wall CW, the firstseating member moves relative to the first confronting wall during theconjoint movement of the seating members and the tool's shank, and thesecond seating member moves relative to the second confronting wallduring the conjoint movement of the seating members and the tool'sshank. Optionally, during the conjoint movement of the seating members50 and the tool's shank S, each seating member moves from a firstposition to a second position and in the process undergoes a change invertical position.

In some embodiments, during the conjoint movement of the seating membersand the tool's shank, at least part of a first of the seating membersslides along a slanted first cam surface of the tool holder and at leastpart of a second of the seating members slides along a slanted secondcam surface of the tool holder.

In some preferred embodiments of the present method, each seating member50 is mounted on the tool holder TH so as to be moveable between firstand second positions, and each seating member is resiliently biased(optionally by one or more spring members) toward the first position.The conjoint movement of such seating members together with the tool'sshank S preferably involves each seating member moving from the firstposition to the second position (in the process overcoming the notedresilient bias). In some embodiments of this nature, for example, thetool-mount channel C opens toward a workpiece location WL, and movementof each seating member 50 from the first position to the second positioninvolves each seating member moving further away from the workpiecelocation. In one embodiment of this nature, a plurality of seatingmembers 50 are mounted along a longitudinal length of the tool holder'sfirst confronting wall CW′, a plurality of seating members 50 aremounted along a longitudinal length of the tool holder's secondconfronting wall CW, and during the movement of the first wall CW′toward the second wall CW all of the seating members move further awayfrom the workpiece location WL.

In the present method, at least one of the seating members 50 optionallycomprises a wedge member at least a portion of which is carriedalongside a cam surface 25 of the tool holder TH. Preferably, this camsurface bears against, and cams with, the wedge member during at leastsome of the movement of the first wall CW′ toward the second wall CW.Such a wedge member can, for example, be mounted on the tool holder THso as to be moveable between first and second positions, such thatduring the camming of the wedge member and the cam surface 25 the wedgemember moves from its first position to its second position by virtue ofat least a portion of the wedge member (e.g., a camming surface thereof)sliding along the cam surface.

In certain preferred embodiments of the present method, the seatingmembers 50 comprise wedge members that bear against, and cam with,respective cam surfaces 25 of the tool holder TH (e.g., during at leastsome of the movement of the first wall CW′ toward the second wall CW).For example, in response to the movement of the first wall CW′ towardthe second wall CW such wedge members preferably sandwich the tool'sshank S and in the process deliver frictional force to the tool's shank.In embodiments of this nature, the frictional force optionally isoriented in a desired direction and causes the tool's shank S to moverelative to the tool holder's cam surfaces 25 until a load-receiptsurface LR of the tool TL engages a load-delivery LD surface of the toolholder TH. The frictional force can be a static frictional force duringthe conjoint movement of the tool's shank and wedge members. In somecases, the conjoint movement of the shank and wedge members (as well asthe static frictional force) ceases once the load-bearing surfaces ofthe tool and tool holder come into engagement. In such cases, furthermovement of the first wall CW′ closer to the second wall CW preferablyresults in the wedge members being forced to move (e.g., due to cammingof the wedge members and tool holder's cam surfaces) relative to thethen stationary shank S of the tool. This relative movement optionallyresults in dynamic friction force (optionally oriented in an upwardvertical direction) being applied by the wedge members to the tool'sshank. Movement of the first wall CW′ toward the second wall CWpreferably ceases when clamping surfaces 95 of the tool holder engageand clamp opposite sides of the tool's shank. At this stage, the toolwill preferably be in its operatively mounted position.

One particular method of operation will now be described with referenceto FIGS. 14 and 15. The illustrated tool TL is initially lifted up intothe tool holder's channel C until an engagement portion 580 of thetool's retractable safety key SK snaps into a safety recess SR definedby the tool holder TH. At this point, the operator can let go of thetool TL and the safety key SK will keep the tool from falling out of thetool holder's channel C (by virtue of the safety key's engagementportion 580 resting on a safety shelf SCS defined by the tool holderTH). It will be appreciated that during the initial step of lifting thetool's shank S into the tool holder's channel C, the tool holder isretained in its open configuration. In the present embodiment, this isaccomplished by virtue of pressurized hydraulic fluid in the actuator Aholding the moveable face plate MP in its open position. To then closethe illustrated tool holder TH, the hydraulic pressure in the actuator Ais reduced so as to allow the springs SP to move the plate MP toward thetool holder's laterally-stationary block CB, in other words moving thefirst confronting wall CW′ toward the second confronting wall CW. As thefirst wall CW′ moves toward the second wall CW, the vertical contactsurfaces 55 of the illustrated seating members 50 engage the tool'sshank S. At this stage, static friction between the seating members 50and the shank S prevents relative movement between the seating membersand the shank. As the first wall CW′ continues moving toward the secondwall CW, the seating members 50 cam with the slanted cam surfaces 25.This camming action forces the seating members 50 to move upwardly, andthe static friction between the seating members and the shank S causesthe tool TL to move upwardly along with the seating members. Thisconjoint upward movement continues until the upwardly-facing horizontalload-receipt surfaces LR of the tool TL come into contact with thedownwardly-facing horizontal load-delivery surfaces LD of the toolholder TH. At this point, further upward movement of the tool isprevented. As the first wall CW′ continues to move further toward thesecond wall CW, the seating members 50 continue to cam with the slantedcam surfaces 25, causing the seating members to continue movingupwardly. In the process, the vertical contact surfaces 55 of theseating members 50 slide upwardly along the tool's shank S, thusapplying an upward dynamic friction force to the shank. This continuesuntil the vertical clamping surfaces 95 of the tool holder TH engage andclamp the tool's shank S, at which point the seating members 50 willhave moved fully into the recesses 70 defined by the tool holder TH.This results in the tool being fully clamped in its operative position.This method, however, is merely one particular embodiment of theinvention.

While preferred embodiments of the present invention have beendescribed, it is to be understood that numerous changes, adaptations,and modifications can be made to the preferred embodiments withoutdeparting from the spirit of the invention and the scope of the claims.Thus, the invention has been described in connection with specificembodiments for purposes of illustration. The scope of the invention isdescribed in the claims, which are set forth below.

1. A tool holder for a press brake, the tool holder being adapted to move a press brake tool in a pressing direction when the tool is operatively mounted on the tool holder, the tool holder having two spaced-apart confronting walls bounding a tool-mount channel, the tool holder having a moveable seating member mounted on one of said confronting walls, the seating member having a contact surface that comes into direct contact with a side of the tool's shank during a closing of the tool holder on the tool's shank, the contact surface being defined at least in part by a polymer.
 2. The tool holder of claim 1 wherein the seating member has a camming surface adapted to bear against, and cam with, a cam surface of the tool holder, the camming surface being defined at least in part by a polymer.
 3. The tool holder of claim 2 wherein the camming surface of the seating member is at an oblique angle relative to the contact surface of the seating member.
 4. The tool holder of claim 2 wherein the cam surface of the tool holder is defined by steel over which coating is provided.
 5. The tool holder of claim 4 wherein said coating comprises nitrogen and/or carbon.
 6. The tool holder of claim 1 wherein the seating member consists essentially of the polymer and a filler.
 7. The tool holder of claim 1 wherein the contact surface once moved into direct contact with the side of the tool's shank delivers a force to the tool's shank, the force being oriented in a seating direction at least generally opposed to the tool holder's pressing direction.
 8. The tool holder of claim 7 wherein the force is a frictional force.
 9. The tool holder of claim 8 wherein the frictional force is the only force oriented in said seating direction applied by the seating member to the tool when the tool's shank is received in the tool-mount channel and the confronting walls of the tool holder are clamped upon the tool's shank.
 10. The tool holder of claim 1 wherein the confronting walls having clamping surfaces for engaging and clamping the tool's shank therebetween, said clamping surfaces being defined by steel over which coating is provided.
 11. A tool holder for a press brake, the tool holder being adapted to move a press brake tool along a pressing axis when the tool is operatively mounted on the tool holder, the tool holder having two spaced-apart confronting walls bounding a tool-mount channel configured for receiving a shank of the tool, the tool holder including moveable seating members disposed on opposite sides of the tool-mount channel, the seating members being adapted to engage opposite sides of the tool's shank and to move together with the shank in a direction at least generally parallel to the tool holder's pressing axis in response to a first of said two walls moving toward a second of said two walls, wherein the seating members are adapted to bear against, and cam with, respective cam surfaces of the tool holder during said conjoint movement of the seating members and the tool's shank, the cam surfaces of the tool holder being defined by bodies comprising a first material, the seating members comprising a second material, wherein the first and second materials are different.
 12. The tool holder of claim 11 wherein the first material comprises steel, and wherein the seating members are formed of material having a lesser hardness than the steel.
 13. The tool holder of claim 11 wherein the second material comprises a polymer.
 14. The tool holder of claim 13 wherein the seating members consist essentially of the polymer and a filler.
 15. A tool holder for a press brake, the tool holder being adapted to move a press brake tool along a pressing axis when the tool is operatively mounted on the tool holder, the tool holder having two spaced-apart confronting walls bounding a tool-mount channel configured for receiving a shank of the tool, the walls having clamping surfaces for engaging and clamping the tool's shank therebetween, the clamping surfaces of the tool holder being defined by metal over which coating is provided.
 16. The tool holder of claim 15 wherein the clamping surfaces of the tool holder are defined by steel over which the coating is provided.
 17. The tool holder of claim 15 wherein said coating comprises nitrogen and/or carbon.
 18. The tool holder of claim 15 wherein an entirety of a first of said two walls is adapted to move relative to a second of said two walls.
 19. The tool holder of claim 15 wherein the tool holder includes moveable seating members disposed on opposite sides of the tool-mount channel, the seating members being adapted to engage opposite sides of the tool's shank and to move together with the shank in a direction at least generally parallel to the tool holder's pressing axis in response to a first of said two walls moving toward a second of said two walls.
 20. The tool holder of claim 19 wherein the seating members comprise a polymer.
 21. The tool holder of claim 20 wherein the seating members consist essentially of the polymer and a filler.
 22. A tool holder for a press brake, the tool holder being adapted to move a press brake tool in a pressing direction when the tool is operatively mounted on the tool holder, the tool holder having two spaced-apart confronting walls bounding a tool-mount channel, the tool holder having a moveable seating member mounted on one of said confronting walls, the seating member having a contact surface adapted to directly contact a side of the tool's shank, the seating member having a camming surface adapted to bear against, and cam with, a cam surface of the tool holder, the cam surface of the tool holder being defined by metal over which coating is provided.
 23. The tool holder of claim 22 wherein the cam surface of the tool holder is defined by steel over which coating is provided.
 24. The tool holder of claim 22 wherein the camming surface of the seating member is defined at least in part by a polymer.
 25. The tool holder of claim 24 wherein the seating member consists essentially of the polymer and a filler.
 26. The tool holder of claim 22 wherein the camming surface of the seating member is at an oblique angle relative to the contact surface of the seating member.
 27. The tool holder of claim 22 wherein the coating comprises nitrogen and/or carbon. 